For dead shells, I have had excellent luck on  St. Croix. Look at the salt
river inlet on the north side of the island. In water about 3 feet deep (we
were snorkling) there are tons of turbans and bubbles. And you can find lots
of  various other stuff. I did find an angular triton (no  I am not looking up
latin names at this time of night) and of course the regular Strombus gigas
which are everywhere. However  the only live mollusk I found was a Fasciolaria
(tulip)  A big one I might add and he/she was munching on a turban. It was a
good thing to show the people who don't know anything about mollusks and their
feeding habits (gotta love them Carnies..) And it kinda shocked my prof.  The
grassbeds in the area are very shallow and easily accessable. It's good
snorkling if you enjoy looking at grass (which I do) At high tide the current
is extremely strong but the water is so shallow that it is easy to manuver.
But at lowtide its too shallow to do anything but trudge through a ton of
grass. On the road there are some various bubbles, canoes, and the usual
neritina, nerita and turbans. On the Mangrove roots (which were in a lot of
trouble because of Hurricane Marilyn) there were some oysters. I don't know
how much of the restored mangroves are left because of Georges. I won't know
what the damage to the ecosystems of the Island until March.  However a little
warning.. DO NOT LEAVE BAGS UNATTENDED ANYWHERE IN THIS AREA. as we found out
(I was one of the smart ones in not bringing anything valuable) we were
totally robbed. One of my professors had $250 in cash taken.  The thieves went
through our bags and took only what they could pawn off or was not traceable.
We figure all the artifacts taken were on St. Lucia the next day being sold.
We lost all together over $1500 worth of money, jewelry etc because we left
the beach with our stuff there.  Of course our guide should have known better
and we should have known better. If you are interested in knowing more about
the harrowing experiences on the island, then email me privately.
 
Sarah Watson
http://www.geocities.com/SouthBeach/Tidepool/8845